Dissolution of bio-active dentine matrix components by mineral trioxide aggregate

Objectives To analyze the soluble components of setting and set mineral trioxide aggregate (MTA), assess the abilities of two varieties of MTA and Ca(OH)2 solutions to solubilise dentine matrix proteins (DMPs) and determine if these extracts contain signalling molecules important to pulpal repair and regeneration. Methods The metallic ion composition of solutions of white and grey MTA (pH 11.7), 0.02 M Ca(OH)2 (pH 11.9) and 10% EDTA (pH 7.2) was determined using atomic absorption spectroscopy. Extracellular dentine matrix components from powdered human dentine were extracted using all solutions over 14 days. Extracts were analysed for concentrations of non-collagenous proteins (NCPs) and glycosaminoglycans (GAGs), and protein profiles were examined using 1D-polyacrylamide gel electrophoresis (1D-PAGE). ELISAs for TGF-β1 and adrenomedullin (ADM) were also performed. Results Aluminium, calcium, potassium, and sodium ions were detected in both white and grey MTA solutions. MTA and Ca(OH)2 solutions liberated similar amounts of GAGs and NCPs although yields were considerably lower than those obtained using the EDTA solution. 1D-PAGE analysis demonstrated differences in protein profiles solubilised from dentine for all solutions. All extracts contained TGF-β1 and ADM, EDTA solution liberated significantly greater amounts of TGF-β1, and Ca(OH)2 and grey MTA solutions released more ADM. Conclusions These data imply that when placed clinically soluble components of set and setting MTA may release dentine matrix components that potentially influence cellular events for dentine repair and regeneration.